Shoe bottoming



All@ 28, ,1955 c. G NEw-roN, JR, ET AL. 2,760,215

SHOE BOTTOMING Filed Oct. 29, 1954 In ven t0 rs Cha/"Zes G New t0n, Jr' Myron A. Perkins, JP.' By hen-gigli? United States Patent snol: orroMrNG Charles G. Newton, Jr., Newburyport, and Myron A. Perkins, Jr., Lynniield, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application October 29, 1954, Serial No. 465,472

1 Claim. (Cl. 12-142) This invention relates to a method of shoemaking, and more particularly to a method of bottoming shoes.

An insole having a firm body and an upstanding rib is the foundation to which an upper, a welt and a sole are linked in a welt shoe. In the manufacture of such a shoe an insole is tacked to a convex last bottom in such fashion that its rib protrudes from the insole bottom. An upper is mounted on the last yand its lower edge is pulled around the edge of the last bottom and attached to the outer face of the rib. A welt is then placed in contact with the shoe upper contiguous with the outside of the rib, and the rib, the upper, and the welt are sewed together. Following this, the upstanding rib and upper are trimmed to a uniform height which is level with the welt. The shoe forepart bottom at this point has a nonuniform cross section with the welt and the trimmed rib and upper being at one level, and the level of the insole inside the rib dropping sharply adjacent to the inner face of the rib and rising gradually toward the center of the insole where it forms a crown. This crown is that portion of the insole forepart which is on a level with or slightly above the welt and trimmed rib and upper. The hollow extending around the insole forepart between the rib and the crown is the cavity.

The forepart of the shoe bottom inside the rib normally is iilled over all in such fashion that the filled shoe bottom parallels the convex bottom of the last, and when a sole is attached to the shoe bottom the sole bottom assumes this convex shape. This lling is of advantage in that the filler supports the sole, the insole and the rib while the shoe is new, and no empty spaces remain within the forepart of the shoe. However, pressures applied to the shoe bottom during walking are localized at the high point of the shoe bottom crown, with the result that the sole wears rapidly. Furthermore, this localization of pressure magnies the pressures applied to the iiller at certain points and the filler shifts within the forepart to form humps and hollows in the insole foot facing and the sole tread surfaces. This unevenness causes extreme discomfort to a wearer of the shoe. An added disadvantage which causes further discomfort to the wearer, lies in the thickness of the combined insole, filler and outsole which results in a shoe which is resistant to flexing.

It is a feature of this invention to provide a method for manufacturing a novel and improved flexible welt shoe, in which the shoe has a substantially straight-across load distributing forepart bottom and a stably smooth l 2,271,760,215 Patented Aug. 28, 1956 ICC shoe the processing of which includes the operations of depositing in the shoe bottom a sufficient quantity of a moldable and hardenable adhesive and filling composition to fill the cavity and to leave the crown of the insole free of the composition, spotting a sole onto the shoe bottom and pressing the sole to the shoe bottom while the composition is in moldable and adhesive condition. The pressing removes any surface irregularities in the composition which remained following deposition of it within the cavity, and establishes a bond between the sole and the shoe which not only serves as a sole laying bond, but which furthermore endures for the life of the shoe. Because of the lack of adhesive and filling composition over the crown of the insole and the resulting straight-across character of the shoe forepart bottom, pressures encountered by the shoe sole during Walking are distributed evenly across the bottom. Accordingly, the sole Wears evenly and therefore slowly, while the composition does not tend to become displaced during wear and the shoe parts are supported for the life of the shoe against shifting and forming humps and hollows in the foot-facing and tread surfaces. Furthermore, because of the lack of composition in the center of the forepart, the combined shoe parts in this area are thin and are free to slip relative to each other within the cement-free area with the result that a flexible shoe is produced.

In the drawings,

Fig. 1 is an angular view of a Welt shoe showing an adhesive and filling composition being deposited into the cavity;

Fig. 2 is a section taken on the line lI-ll in Fig. 1; and

Fig. 3 is a section similar to Fig. 2 showing a sole bonded to the shoe.

The shoe 10 prepared according to the method of the present invention includes van insole 12 having a rib 14 and a cavity 16 and has a welt 18 attached to the rib. A sole 20 is attached to the welt 18 by means of an adhesive and filling composition 22 which bonds the sole 20 adhesively to the shoe bottom and supports the shoe parts against shifting, and further by means of an outseaming thread 24 which stitches the sole to the welt.

Turning now to Figs. 1 and 2, -a shoe 10 having an insole 12 is shown mounted on the last 26. The insole 12 which is of a well-known type may be of leather and is provided with outside and inside rib forming channels 28 and 30, the flaps 32 of which are turned up and bonded together to form the upstanding rib 14. A cavity 16 is formed on the insole bottom 34 when the insole is mounted on the last 26 and an upper 36 and a welt 18 are stitched to the outer face 38 of the rib 14 with an inseaming thread 40 pulling the edges 42 of the insole 12 tight to the normally convex last bottom 44. This conformity of the insole with the convex last bottom causes the center of the insole to protrude relative to the edges of the insole, thereby forming a crown 46 on the insole bottom 34. The upstanding rib 14 and the upstanding portions of the upper 36 are trimmed to a height approximately level with the crown 46 which in a typical shoe extends roughly 5716 of an inch above the deepest portion of the cavity 16, i. e. the inside rib forming channel 30, and is approximately 1/2 of an inch or more wide Iat its widest point and one to two inches long. The area covered by this crown is dependent upon the radius of curvature of the crown of the last bottom and upon the rib height, and is outlined by the intersection of the insole bottom and a plane which is established by the'top of the major part of the upstanding trimmed rib in the forepart area. The toe of the shoe normally curves away .from this plane and thus the rib in that area does not contact the plane. Thus the area of this crown in .anyshoe is determinedby the degree of Vconvexity of the last bottom and the height of the rib, which vary with the individual shoe style. For purposes of 'this invention, however, yit is preferred that these factors be controlled to provide acrown which is at least 1/2 -of an inch Wide at lits widest'point and at least :one finch long. This is because in either machine or hand filling Iof the 'cavity `it is of importance that a reasonably large crown exists in the shoe bottom to serve as a registering and steadying means for vthe filling tool, and because 4a smaller crown makes it ydifficult -to -fill the cavity Without covering the crown. The hollow `in the insole bottom between the inner face 48 of ythe upstanding rib 14 .and the outline of `the kcrown -46 'forms the cavity which is wedge shaped in section and decreases gradually Tfrom -a depth of approximately 3/16 of an inch in its deepest section adjacent to the rib until it terminates in an edge where it meets the crown.

Other insoles suitable for use in welt shoes :may be employed with equal ultimate advantage in the present invention. An alternate insole is a leather insole having a rib cemented to it. It is obvious that a cavity generally similar to that described yabove but not including :the rib-forming channel thereof is formed on this insole bottom. when the insole is mounted on a last and an upper and a Welt are attached to its rib.

According to the Imethod of this invention, a moldable, hardenable, adhesive and filling composition `22 is deposited within the cavity 16 (see Fig. 1.) 4of the insole 12 where it serves to support the rib 14 and to fill the cavity 16 to a height level with the rib 14 and the crown 46. It is important that the composition 22 be free of large, non-moldable particles which would interfere vwith the production of a smooth, even surface on the body of the composition, particularly where the composition is present in a thin section adjacent to the insole crown. This smoothness of surface is-desirable in the shoe where it permits of smooth foot-facing and tread surfaces. Accordingly, such non-moldable particles should be of a size `to pass through a 20 mesh sieve.

By the preferred method the composition 22 is placed on a spatula 50 and the spatula is wiped around 'the shoe bottom to spread a cavity filling quantity of the composition, while it is in moldable and adhesive condition, within the cavity 16. Often it is preferred also to spread a film `52 of the composition 22 over the welt 18 during the spreading operationto enlarge the area of composition subsequently available for bonding the sole 20 to the shoe. However, in the specification and claims the term cavity filling quantity is intended 'to mean )a quantity of adhesive and filling composition suflicient only to fill 'the cavity 16 to the level of the rib 14 and the crown 46, and to leave the crown 46 free of the composition 22. Thus the shoe bottom containing the adhesive and filling composition 22 presents a substantially straight-across, load distributing surface which is assumed by the fiat outsole 20 when the latter is attached toit. When the cavity 16 is filled in Vthis lfashion the composition 22 is in position to support the insole rib 1'4, the insole 12 and the sole 20 of the shoe y10 evenly, and because of this evenness does not tend to shift out of position vitself or to permit these shoe parts yto shift when the shoe 'is finished and worn. A depositing method more suitable for use with automatic machinesand which may be use'd with equal ultimate advantage, 'comprises extru'ding the composition from a lsuitable 'nozzle within 'the :desired area. The presence of'a-'substantial -crownpermits use of a machine which registers the 'width 'and depth of the cavity to be filled. Thus a device on the machine can be designed to ride alongthe outline of the crown 46 and the rib 14 as a means for locating the cavity 16.

Either prior to or after deposition of the adhesive land lfilling composition 22 within the'cavity 16, a shakpiece v54 is -tacked'withtacks 56 tothe insole'bottom 34. Following deposition 'of the composition '46 'and attachment Vof the shank S4, it is necessary to bond a sole20 to the shoe bottom. This bond, which is of an adhesive nature and is augmented later when the sole 20 is sewed with an outseaming thread 24 to the welt 18, is of great importance during the shoemaking where it is relied upon to maintain the sole on the shoe bottom during the rough rounding and stitching operations, and further is of extreme importance in the finished shoe where it combines with the mechanical bond produced by the sewing to stabilize the shoe parts, e. g. the insole rib 14, the soles 12 and 20, and the welt 18 against shifting.

It has been found advantageous to bond the sole forepart to the shoe forepart bottom in an area which excludes only the crown 46 in the center of the insole forepart. Thus in a typical mens Goodyear welt shoe an area of approximately 15.5 square inches is utilized as a bonding area out of a total forepart area of approximately 17 square inches, anda bond is derived which stabilizes the shoe parts, i. e. the sole 20, the insole 12, the rib 14, and the adhesive and filling composition 22, against shifting during wear and thus producing a shoe having humps and hollows on its foot-facing tread surfaces. ln spite of its stabilizing action, however, the bond does not extend to the crown 46 of the insole 12 and thus does not eliminate that slight slippage between the sole 20 and the insole 12 which is an important element in providing a flexible shoe.

Frequently, the moldable, hardenable adhesive and filler composition 22 which is to be used as a sole bonding adhesive hardens and loses its moldability and adhesiveness before the sole bonding operation is performed. When this occurs, it is necessary to activate the composition 22 prior to sole bonding to render it moldable and adhesive. When a heat activatable composition is used the filled shoe bottom is heated, for example with infrared radiation, vfor a short time (approximately 10 seconds), the sole 20 is spotted onto the shoe bottom while the composition 22 remains moldable and adhesive and the sole 20 is pressed to the shoe bottom in a sole laying machine for approximately five seconds. Following the pressing operation the shoe is removed from the machine. The pressing completes the leveling of the adhesive and filling composition 22 which had a somewhat rough surface following its deposition, and furthermore presses the sole 20 into bonding relationship with the shoe bottom.

Following bonding to it of the sole 20, the shoe 10 is completed according to usual shoemaking procedures. The sole 20 is sewed to the welt 18 with an outseaming thread 24, it is rough rounded, i. e. the sole 20 is cut to conform roughly to its desired final outline, the heel is attached to the shoe and the shoe is `finished by conventional means.

It is important that the adhesive and filling composition 22 employed exhibit substantial adhesiveness toward the shoe parts with which it comes in contact. This adhesiveness should be sufficient to maintain the shoe parts in bonded relationship for the life of the shoe and to pull a large 'amount of ber from the leather shoe parts with which it is bonded when the shoe is pulled apart. VIt is important further that it be available in a moldable condition to allow deposition of it within an insole cavity 16, that lit be hardenable to a firm consistency and that it have `substantial strength. Thus it should be sufficiently strong to provide support tothe rib 14 and the soles 12 and 20 and to resist forces which would tend to crumble a highly weak and friable material. In this connection it should be noted that formation of cracks and splits in the composition does not impair its efficiency provided these cracks and splits are not extensive enough to cause it to shift.

Thechemical nature 'of the composition will vary as different sole materials, e. g. leather, vinyl resins, Buna-'S rubber, etc., are used in the shoe in order that the composition may exhibit proper adhesiveness toward1 the shoe parts. Thermoplastic resins which can be activated with heat and/or solvent to moldable adhesive condition, such as polyamide resins, vinyl chloride-vinyl acetate resins, reclaimed rubber-rosin blends, polystyrene resins, and the like and/or moldable thermosetting materials which set to a hard condition, such as polyester resins, aldehyde resins, vulcanizable rubber compositions, epoxy resins and similar materials are suitable for use in the present invention either alone or mixed with other resins and/or in combination with plasticizers, fillers, curing agents and other compounding ingredients. Nonmoldable fillers employed herein should be of a particle size, i. e. less than 20 mesh, which permits the obtaining of a smooth, thin section of the composition in the area adjacent to the insole crown 46. When excessively large non-moldable ller particles are used it is difiicult to spread the composition in that thin section of the cavity 16 and maintain the smooth surface on the shoe bottom which is of advantage in obtaining a comfortable shoe. It is important further that the adhesive and filling composition chosen have a sufficiently high melting temperature to avoid shifting of the shoe parts which occurs when an adhesive and filling composition having too low a softening temperature softens during wear. Thus it is preferred that the composition have a softening tem-- perature above 120 F.

Example A Goodyear welt shoe upper 36 was lasted to a leather insole 12 having a cavity 16 and a rib 14. A leather welt 18 was then inseam stitched to the shoe 10 with an inseaming thread 40, the rib 14 and upper 36 were trimmed to a height approximating that of the center or crown 46 of the insole 12 and a steel shank piece 54 was tacked into the shank area of the shoe with tacks 56 (see Fig. 1). Following these operations a thermoplastic adhesive and filling composition 22 was heated to approximately 325 F., at which temperature it became a viscous, adhesive liquid, and was spread with a spatula 50 into the cavity 16 of the insole 12 (see Fig. 1). The thermoplastic adhesive and filling composition employed was:

Parts by weight Polyamide 94S 50 Polyamide 95S 50 shoe bottom and pressed thereto in a sole laying machine for approximately five seconds at lbs. per square inch of pressure. The shoe as it was removed from the sole laying machine had a smooth insole foot-facing surface 58 and a smooth, substantially straight-across, load distributing outsole tread surface 60, and its parts were bonded together strongly.

The shoe then was rough rounded and its sole 20 was outseam stitched to the welt 18 with an outseaming thread 24. No separation of the sole 20 from the shoe 10 was noted during these operations. The shoe was then heeled and finished by conventional means. A test subject who wore the shoe related that it was comfortable and its sole was found to have worn evenly due to the absence of wear-producing humps on its tread surface. Furthermore, the foot-facing surface of the insole remained smooth during the period of wear, indicating that the shoe parts had not shifted.

Thus, practice of the method of the present invention results in the production of a welt shoe having a uniform appearance and having the further desirable characteristics of long wear and comfort.

Having thus described the invention, what we claim as new and desire to secure by Letters Patent of the United States is:

Method for producing a welt shoe comprising an upper, an insole having a rib, and having a crown in the center of its forepart bottom, a welt attached to said insole rib and to said upper, a cavity bounded by the inner face of said insole rib and the outline of said insole crown, and an outsole, and having a substantially straight-across, load distributing forepart bottom, a smooth foot-facing insole surface, support for said forepart bottom and said insole surface and a bond between a shoe sole and the forepart bottom, which method comprises depositing a moldable, hardenable adhesive and filler composition free of non-moldable particles of a size greater than 20 mesh within the cavity of an insole leaving the crown of the insole free of said composition, said crown being at least 1/2 of an inch wide at its widest point and at least one inch long, spotting a sole onto the forepart bottom in contact with said composition and pressing said sole to said forepart bottom to establish a bond with and to smooth the forepart bottom.

References Cited in the le of this patent UNITED STATES PATENTS 1,573,528 Sorensen Feb. 16, 1926 1,656,564 Lyon Ian. 17, 1928 1,756,169 Benda Apr. 29, 1930 2,042,483 Richardson .lune 2, 1936 2,074,166 Condon Mar. 16, 1937 2,080,531 Bunker May 18, 1937 

